Macromolecules and Polymers Quiz

Macromolecules

• Macromolecules are large molecules composed of thousands of covalently bonded atoms.
• The four main classes are carbohydrates, proteins, nucleic acids, and lipids.
• Polymers are long molecules consisting of many similar building blocks linked by covalent bonds.
• Monomers are the repeating units that serve as the building blocks of polymers.

Making and Breaking Polymers

• Dehydration reaction: Two monomers are covalently bonded together by removing water.
• Hydrolysis reaction: Polymers are disassembled (broken down) into monomers using water.
• Digestion is an example of hydrolysis followed by dehydration reactions.

Carbohydrates

• Carbohydrates contain a carbonyl group (C=O) and multiple hydroxyl groups (─OH).
• There are three types of carbohydrates: monosaccharides (simple sugars), disaccharides (double sugars), and polysaccharides (complex sugars).
• Examples of polysaccharides include starch, cellulose (plants) and glycogen (animals).

Lipids

• Lipids are not polymers.
• They are hydrophobic due to their nonpolar covalent bonds.
• Lipids consist mostly of hydrocarbon regions.
• There are three main types of lipids: fats, phospholipids, and steroids.

Fats

• Fats are composed of glycerol and fatty acids joined by ester linkages.
• A fat molecule with three fatty acids is called a triacylglycerol or triglyceride.
• Fats are the primary form of energy storage in organisms.

Types of Fats

• Saturated fatty acids have only single bonds between carbon atoms and are solid at room temperature (e.g., butter, beef fat).
• Unsaturated fatty acids have one or more double bonds between carbon atoms and are liquid at room temperature (e.g., olive oil, linseed oil).
• Some unsaturated fatty acids are essential and must be obtained from the diet (e.g., omega-3 fatty acids).

Phospholipids

• Phospholipids consist of a phosphate group, two fatty acids, and glycerol.
• They form the lipid bilayer of cell membranes.

Steroids

• Steroids are composed of four fused rings with attached chemical groups.
• Examples of steroids include sex hormones and cholesterol.
• Cholesterol is a common component of animal cell membranes and acts as a precursor for the synthesis of other steroids.

Proteins

• Proteins are polymers composed of amino acids.
• There are 20 different types of amino acids.
• Proteins have many functions, including speeding up chemical reactions, defense, storage, transport, cellular communication, movement, and structural support.

Amino Acid Structure

• All amino acids share a common structure with an alpha (α) carbon attached to an amino group (H-N-H), a carboxyl group (O=C-OH), a hydrogen atom, and a variable R side chain.
• The R side chain determines the properties of the amino acid.

Levels of Protein Structure

• Primary structure: The linear sequence of amino acids linked by peptide bonds.
• Secondary structure: Hydrogen bonds form between adjacent amino acids in the polypeptide backbone, resulting in alpha helices or beta sheets.
• Tertiary structure: Interactions between R groups of amino acids (e.g., van der Waals interactions, hydrogen bonds, ionic bonds, disulfide bridges) cause the polypeptide to fold into a specific 3-dimensional shape
• Quaternary structure: Aggregation of two or more polypeptide chains to form a biologically functional protein.

Protein Structure and Function

• Protein structure is influenced by environmental factors such as pH, salt concentration, and temperature.
• Protein function depends on its structure.
• Denaturation is the disruption of a protein's 3D structure, leading to loss of function.

Nucleic Acids

• Nucleic acids are polymers composed of monomers called nucleotides.
• Each nucleotide consists of a phosphate group, a sugar (pentose), and a nitrogenous base.
• The two main types of nucleic acids are DNA and RNA.

DNA (Deoxyribonucleic Acid)

• DNA is a double-stranded molecule (double helix) with complementary base pairing (A-T, C-G).
• The two strands are antiparallel (running in opposite directions).
• DNA serves as the genetic blueprint for organisms, containing the instructions for building and maintaining life.
• The sugar in DNA nucleotides is deoxyribose.
• The nitrogenous bases in DNA are adenine (A), thymine (T), cytosine (C), and guanine (G).

RNA (Ribonucleic Acid)

• RNA is a single-stranded molecule.
• The sugar in RNA nucleotides is ribose.
• The nitrogenous bases in RNA are adenine (A), uracil (U), cytosine (C), and guanine (G).
• RNA plays a vital role in protein synthesis.

DNA and RNA Code

• Both DNA and RNA contain genetic code that specifies the sequence of amino acids in proteins.